The Effects Of Shock Wave On Osteoporotic Fracture Healing In Bilateral Ovariectomized Rats

PARTⅠEffects of high energy shock waves on the bone structure and mechanical strength in Osteoporotic ratsObjective To investigate the influence of the high energy shock waves on the bone structure and mechanical strength in experimental osteoporosis.Methods Eighteen female SD rats were underwent ovariectomy (OVX) to establish the osteoportic models. Three months after OVX ,the left limb (the study side) received shock wave therapy( 0.26 mJ/mm2 energy flux density with 1000 impulses )to the proximal femur. The right limb (the control side) received no shock wave therapy. Biopsies of the the proximal femurs were performed and each of them was examined by by micro-CT, bone histomorphometry, biomechanical testing at 6 weeks after treatment.Results Microstructure of the trabecular bone in proximal femur 6 weeks after treatment showed that the Density of TV, BV/TV, Tb.Th, Tb.N at the study side increased significantly Compared with the control side, however the BS/BV, Tb.Sp, SMI and MAR decreased significantly(P<0.01). In biomechanical testing, the maximum compressing strength of trabecular bone in the study side 6 weeks after treatment was higher than that in control side(P<0.05).Conclusion High energy shock wave treatment can accelerate the bone formation, increase the bone density, decreasing the rate of bone turnover and the good change of the microstructure, improve the bone quality and bone biomechanical strength. fracture in rats, and improves the mechanical strength. It maybe a alternative method to local treatment of osteoporosis and osteoporotic fractures clinically. PARTⅡThe effects of shock wave on osteoporotic fracture healing in ratsObjective To investigate the therapeutic effect of the high energy shock waves on osteoporotic fracture in rats.Methods Forty-five 14-week-old female Sprague-Dawley rats were underwent bilateral ovariectomy.Three months later when the osteoporosis was confirded by BMD examination.the 40 rats had their left femoral shaft fractured.After selection 32 rats finally enter the experiment. One week later,32 rats were divided randomly into two groups: treatment group and control group.The left femur of rats in treatment group were received shock wave therapy(0.26mj/mm2energy flux density with 1000 impulses).The radiography of the left femurs were performed at 3 and 6 weeks after treatment.Six weeks after treatment,the rats were sacrificed and their left femurs taken for histological study and biomechanical analysis.Results Compared with the control group,the HESW treated femurs showed more rapid bone healing,accelerated endochondral bone formation and more bone remodeling.The biomechanical testing revealed that,the maximum torque and torsion stiffness were 0.76±0.09 versus 0.59±0.07,0.13±0.01 versus 0.05±0.01,respectively.The maximum torque and torsion stiffness of HESW group were significantly higher than those of the control(P<0.05).Conclusion High-energy shock wave significantly accelerates the healing of osteoporotic fracture in rats,increases the bone mineral density,and improves the mechanical strength of the callus, thus providing a new ideas and methods for the clinical treatment of osteoporotic fractures.